# curs_kernel 3x

    curs_kernel(3x)                                         curs_kernel(3x)

## NAME

           def_prog_mode, def_shell_mode, reset_prog_mode,
           reset_shell_mode, resetty, savetty, getsyx, setsyx,
           ripoffline, curs_set, napms - low-level curses routines

## SYNOPSIS

           #include <curses.h>

           int def_prog_mode(void);
           int def_shell_mode(void);
           int reset_prog_mode(void);
           int reset_shell_mode(void);
           int resetty(void);
           int savetty(void);
           void getsyx(int y, int x);
           void setsyx(int y, int x);
           int ripoffline(int line, int (*init)(WINDOW *, int));
           int curs_set(int visibility);
           int napms(int ms);

## DESCRIPTION

           The  following  routines  give low-level access to various
           curses capabilities.  Theses routines typically  are  used
           inside library routines.

           The  def_prog_mode  and  def_shell_mode  routines save the
           current terminal modes as the  "program"  (in  curses)  or
           "shell"   (not  in  curses)  state  for  use  by  the  re-
           set_prog_mode and reset_shell_mode routines.  This is done
           automatically by initscr.  There is one such save area for
           each screen context allocated by newterm().

           The reset_prog_mode and reset_shell_mode routines  restore
           the  terminal  to "program" (in curses) or "shell" (out of
           curses) state.  These are  done  automatically  by  endwin
           and,  after  an  endwin, by doupdate, so they normally are
           not called.

           The resetty and savetty  routines  save  and  restore  the
           state  of  the  terminal modes.  savetty saves the current
           state in a buffer and resetty restores the state  to  what
           it was at the last call to savetty.

           The  getsyx routine returns the current coordinates of the
           virtual screen cursor in y and x.  If leaveok is currently
           TRUE,  then -1,-1 is returned.  If lines have been removed
           from the top of the screen, using ripoffline, y and x  in-
           clude  these lines; therefore, y and x should be used only
           as arguments for setsyx.

           The setsyx routine sets the virtual screen cursor to y, x.
           If y and x are both -1, then leaveok is set.  The two rou-
           tines getsyx and setsyx are designed to be used by  a  li-
           brary  routine,  which manipulates curses windows but does
           not want to change the current position of  the  program's
           cursor.   The library routine would call getsyx at the be-
           ginning, do its manipulation of  its  own  windows,  do  a
           wnoutrefresh  on  its  windows, call setsyx, and then call
           doupdate.

           The ripoffline routine provides access to the same facili-
           ty  that  slk_init  [see  curs_slk(3x)] uses to reduce the
           size of the screen.   ripoffline  must  be  called  before
           initscr or newterm is called.  If line is positive, a line
           is removed from the top of stdscr; if line is negative,  a
           line is removed from the bottom.  When this is done inside
           initscr, the routine init (supplied by the user) is called
           with  two arguments: a window pointer to the one-line win-
           dow that has been allocated and an integer with the number
           of columns in the window.  Inside this initialization rou-
           tine, the integer variables LINES  and  COLS  (defined  in
           <curses.h>) are not guaranteed to be accurate and wrefresh
           or doupdate must not be called.  It is allowable  to  call
           wnoutrefresh during the initialization routine.

           ripoffline  can  be called up to five times before calling
           initscr or newterm.

           The curs_set routine sets the cursor state is set  to  in-
           visible,  normal,  or very visible for visibility equal to
           0, 1, or 2 respectively.  If  the  terminal  supports  the
           visibility  requested,  the  previous  cursor state is re-
           turned; otherwise, ERR is returned.

           The napms routine is used to sleep for ms milliseconds.

## RETURN VALUE

           Except for curs_set, these routines always return OK.

           curs_set returns the previous cursor state, or ERR if  the
           requested visibility is not supported.

           X/Open  defines  no error conditions.  In this implementa-
           tion

                  def_prog_mode, def_shell_mode, reset_prog_mode, re-
                  set_shell_mode
                       return an error if the terminal was  not  ini-
                       tialized,  or  if  the  I/O call to obtain the
                       terminal settings fails.

                  ripoffline
                       returns an error  if  the  maximum  number  of
                       ripped-off  lines exceeds the maximum (NRIPS =
                       5).

## NOTES

           Note that getsyx is a macro, so & is not necessary  before
           the variables y and x.

           Older  SVr4  man  pages  warn  that  the  return  value of
           curs_set "is currently  incorrect".   This  implementation
           gets  it  right, but it may be unwise to count on the cor-
           rectness of the return value anywhere else.

           Both ncurses and SVr4 will  call  curs_set  in  endwin  if
           curs_set  has  been  called  to make the cursor other than
           normal, i.e., either invisible or very visible.  There  is
           no  way  for ncurses to determine the initial cursor state
           to restore that.

## PORTABILITY

           The functions setsyx and getsyx are not described  in  the
           XSI  Curses standard, Issue 4.  All other functions are as
           described in XSI Curses.

           The SVr4 documentation describes setsyx and getsyx as hav-
           ing  return  type  int.  This  is  misleading, as they are
           macros with no documented semantics for the return  value.

## SEE ALSO

           curses(3x),  curs_initscr(3x),  curs_outopts(3x), curs_re-
           fresh(3x), curs_scr_dump(3x), curs_slk(3x)

                                                            curs_kernel(3x)